64-bit mode with Source SDK
The current Source SDK release has issues starting up on systems running the Source engine in 64-bit mode with the 64-bit version of Windows XP.
To correct the problem:
- In the Steam Games window, right-click on Half-Life 2 (or any installed Valve game you want to run) and select the Properties option.
- Then select Set launch options... and add the line
-32bitto the edit box.
- Close the dialog and launch the game you just edited (ie. Half-Life 2). When it has successfully started up, close the game.
You should now be able to run the SDK on your 64-bit OS. Note, however, that if you run any of your Valve games without the
-32bit option, your SDK will go back to being incompatible and you'll need to repeat this process.
This means that if you run a game through Hammer, you'll also need to launch that game with the
-32bit command line parameter as well. The same is true running a game from a batch file, command line, etc.